The present invention relates to a concrete embedded insert, called an anchor bolt locator, for properly locating and supporting a bolt or anchoring member during the pouring and curing of a concrete member, such that bolt will be properly placed in the cured concrete.
A concrete slab member is a common structural element of modern buildings. Horizontal slabs of steel-reinforced concrete are used to construct slab foundations, floors, ceilings, decks and exterior paving.
Concrete slabs are built using formwork—a type of boxing into which the wet concrete is poured. Typically, if the slab is to be reinforced, steel reinforcing rods are used, and these are positioned within the formwork before the concrete is poured. This steel reinforcing is often called rebar. Plastic tipped metal, or plastic bar chairs are typically used to hold the reinforcing rods away from the bottom and sides faces of the formwork, so that when the concrete sets it completely envelops the reinforcing rods. For a slab resting on the ground, the formwork may consist only of sidewalls pushed into the ground. For a suspended slab, the formwork is shaped like a tray, often supported by a temporary scaffold until the concrete sets. The formwork is commonly built from wooden planks and boards, plastic, or steel. After the concrete has set the formwork can be removed or remain in place. In some cases formwork is not necessary—for instance, a ground slab surrounded by brick or block foundation walls, where the walls act as the sides of the tray and the hardcore earth acts as the base.
Concrete slab members are also typically built in a manner that allows for anchor members and fasteners to be built into the slab so that other building elements can be easily and securely anchored to the concrete member. It is very common to see a slab with many different bolts and fasteners protruding from the slab after it has cured and the formwork has been removed. These preset anchors or inserts are typically used for securing pipes or conduits to concrete ceilings, or for securing framing to a concrete foundation or floor.
When anchors such as bolts and threaded rod are to be embedded in a concrete slab, they must be supported during the concrete pour. It is important that the anchors are located properly in the slab and remain undisturbed during the pour, so that subsequent building elements can be attached to them properly. The proper location of anchors in slabs is especially important for decks where the anchor will fasten a safety railing to the deck and for lateral force resisting systems where the anchors must be placed carefully to provide the proper anchorage without interfering with other structural members. Proper location is also important for the integrity of the anchor and the strength of the anchorage. If the anchor is set too close or at an improper angle so that it is too close to the sides of the slab water penetrating into the slab can degrade the anchor, and the strength of the anchorage is also compromised if there is insufficient concrete surrounding the anchor.
Typically, certain of the anchors located in the slab will be located close enough to the edges of the slab that they can be supported by a member attached to the side formwork during the pour. Other anchors will be located sufficiently far away from the sides of the form that they must be supported in some other manner. Sometimes the anchors can be tied to and supported by the reinforcing rods. Other times it is preferable to support the anchor on the underlying surface of the formwork. The present invention is a free-standing anchor bolt locator that attaches to the underlying formwork and holds an anchor or bolt during the concrete pour. Many such devices appear in the patent literature, including: U.S. Pat. No. 5,957,644, granted Sep. 28, 1999, to James A. Vaughan, U.S. Pat. No. 5,050,364, granted Sep. 24, 1991, to Michael S. Johnson et. al., and U.S. Pat. No. 5,205,690, granted Apr. 27, 1993, to Steven Roth.
The present invention improves upon the prior art by providing an anchor bolt locator that is inexpensively manufactured on automatic die-press machines from sheet steel and a structural nut that does not require any welding, while also being easy to use and install with current, commonly-used building practices and anchor designs.